JP2011036081A - Charging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and quickly charge an externally connected battery, even in a state with an output from a natural-energy generator fluctuating and reducing the residual capacity of a built-in battery. <P>SOLUTION: A charging system consists of the natural-energy generator 2 and a charger 1, which includes the built-in battery 4 charged by the natural-energy generator 2 and a controller 5 for controlling charging to the externally connected battery 3 from the built-in battery 4. The charging system charges the externally connected battery 3, by changing over an internal-battery charging state charging the built-in battery 4 by the natural-energy generator 2 and an external-battery charging state charging the externally connected battery 3 by discharging the built-in battery 4. The charging system changes over the external-battery charging state to the internal-battery charging state, when the voltage of the built-in battery 4 lowers to an extinction voltage in the external-battery charging state. The charging system changes over the internal charging state to the external-battery charging state, when the voltage of the built-in battery 4 increases to a discharge restart voltage in the internal charging state; and the charging system charges the externally connected battery 3, by repeating the external-battery charging state and the internal-battery charging state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charging system, such as a solar battery, which converts natural energy whose output fluctuates into electricity, charges an internal battery, and charges an external connection battery connected to the outside with the internal battery.

Solar chargers that charge batteries with solar cells have been developed. (See Patent Document 1)
This solar charger charges a built-in battery with a solar battery, and charges an external connection battery with the charged built-in battery. In this solar charger, the internal battery is charged with the output of the solar battery, and then the external connection battery is charged with the charged internal battery. In the above solar charger, the rated capacity, which is the full charge capacity of the internal battery, is made larger than the rated capacity of the external connection battery so that the external connection battery can be fully charged with the charged internal battery.

JP 2008-104249 A

  Since the above solar charger charges the internal battery with the solar battery and charges the external connection battery with the charged internal battery, the external connection battery cannot be charged while charging the internal battery with the output of the solar battery. For this reason, if the external connection battery is connected in a state where the internal battery is not sufficiently charged, the external connection battery cannot be charged with the internal battery. In particular, solar chargers that charge externally connected batteries with built-in batteries stop discharging the internal battery and charge the externally connected battery when the remaining capacity of the internal battery is exhausted to prevent overdischarge of the internal battery. Like to stop.

  The solar charger is a circuit configuration that can charge both the internal battery and the external connection battery together with the output of the solar battery, and can charge the external connection battery with a small remaining capacity of the internal battery. However, in order to realize this, it is necessary to use a solar battery having an output larger than the charging current of the external connection battery, or to make the charging current of the built-in battery smaller than the output of the solar battery. Large output solar cells are large and expensive, and if the charging current of the externally connected battery is reduced, the charging time becomes longer and charging cannot be performed quickly.

  Furthermore, since a solar cell converts natural energy into electrical energy, it cannot be used in a state where a rated output is always obtained. For example, when it becomes cloudy or rainy, the output of the solar cell decreases, and fluctuates and becomes unstable. When the output of the solar battery becomes smaller than the current for charging the external connection battery in this state, it becomes impossible to make both the external connection battery and the built-in battery into the state by the output of the solar battery. Therefore, the internal battery is discharged, and the external connection battery is charged with the internal battery. When this state continues, the remaining capacity of the built-in battery gradually decreases, so that the discharge of the built-in battery is stopped and the externally connected battery is not charged in order to prevent overdischarge. In this state, the built-in battery is charged to the solar battery. When the built-in battery is fully charged, charging of the built-in battery is stopped, and the external connection battery can be charged. However, since the built-in battery has a large rated capacity so that the externally connected battery can be fully charged, it takes a considerable time until the built-in battery is fully charged by the solar battery. For example, in a solar charger that requires 3 days to fully charge the internal battery with the output of the solar battery, it is necessary to charge the internal battery for 3 days before the external connection battery can be charged.

  The present invention has been developed for the purpose of solving the above drawbacks. An important object of the present invention is charging that allows an externally connected battery to be efficiently and quickly charged with the output of a solar battery even when the output of a natural energy generator such as a solar battery fluctuates and the remaining capacity of the internal battery is small. To provide a system.

Means for Solving the Problems and Effects of the Invention

  The charging system of the present invention comprises a natural energy power generation device 2 that converts natural energy into electricity, and a charger 1 connected to the natural energy power generation device 2. The charger 1 includes an internal battery 4 that is charged with electric power input from the natural energy power generation device 2, and a control unit 5 that controls charging of the externally connected battery 3 connected to the outside with the internal battery 4. ing. The charging system charges the internal battery 4 of the charger 1 with the generated power input from the natural energy power generation device 2 and discharges the internal battery 4 to charge the external connection battery 3. The control unit 5 supplies power from the built-in battery 4 to the external connection battery 3 to charge the external connection battery 3, and power input from the natural energy power generation apparatus 2 after stopping the external battery charge state The switching unit 6 for switching the internal battery charging state for charging the internal battery 4 with, the discharge stop voltage for the internal battery 4 for switching the external battery charging state to the internal battery charging state, and switching from the internal battery charging state to the external battery charging state A storage circuit 7 for storing a discharge resumption voltage set to a voltage lower than the full charge voltage of the internal battery 4 and a voltage detection circuit 8 for detecting the voltage of the internal battery 4 are provided. The charging system is a discharge in which the voltage of the internal battery 4 is detected by the voltage detection circuit 8 and the detected voltage is stored in the storage circuit 7 in the external battery charging state where the internal battery 4 supplies power to the external connection battery 3. When the voltage drops to the stop voltage, the switching unit 6 switches the external battery charging state of the internal battery 4 to the internal battery charging state, and when the internal battery 4 is charged by the natural energy generator 2 in the internal battery charging state. When the voltage of the built-in battery 4 is detected by the voltage detection circuit 8 and the detected voltage rises to a discharge resumption voltage set lower than the full charge voltage of the built-in battery 4 stored in the storage circuit 7, the switching unit 6 switches the internal battery charging state of the internal battery 4 to the external battery charging state, and repeats the external battery charging state and the internal battery charging state to charge the external connection battery 3.

  The above charging system is characterized in that the external connection battery can be efficiently and quickly charged with the output of the solar battery even when the output of the natural energy power generation device such as the solar battery fluctuates and the remaining capacity of the built-in battery is small. . This is because the charging system described above charges the external connection battery with both the built-in battery and the solar battery while repeatedly charging and discharging the built-in battery without fully charging the built-in battery with the output of the solar battery.

  FIG. 1 is a graph showing a state in which an externally connected battery is charged in a state where the output of a solar battery that is a natural energy power generation device fluctuates. In this figure, curve A shows the voltage change of the internal battery, curve B shows the charging current of the external connection battery, curve C shows the output current of the solar battery, curve D shows the charging voltage of the external connection battery, Curve E shows the input voltage from the solar cell. In a state where the output of the solar cell fluctuates as shown by the curve C, the external connection battery is charged with a large current (a current of about 100 to 500 mA can be used) at a predetermined time interval as shown by the curve B. . The voltage of the internal battery gradually decreases at the timing of charging the external connection battery. When the voltage of the built-in battery drops to the discharge stop voltage (3.3 V in this figure), the discharge is stopped. In the state where the discharge of the internal battery is stopped, the output of the solar battery charges the internal battery. Therefore, when the voltage of the internal battery rises to the discharge resumption voltage set lower than the full charge voltage, the internal battery is switched to charge the external connection battery. Since the built-in battery can output a larger current than the solar battery, the external connection battery is quickly charged with a large current. When the built-in battery that charges the external connection battery is discharged and the voltage drops to the discharge stop voltage, the discharge of the built-in battery is stopped again, and the built-in battery is charged with the solar battery. This process is repeated to charge the external connection battery. The above charging system repeats the internal battery charging state in which the output of the solar battery is stored in the internal battery and the external battery charging state in which the electric power stored in the internal battery is output to the external connection battery, in particular, the electric power stored in the internal battery. While controlling the discharge stop voltage and discharge restart voltage to the optimum values, the external connection battery is quickly charged by efficiently using the output of the solar battery.

In the charging system of the present invention, the natural energy power generation device 2 can be the solar battery 20.
The above charging system can charge the external connection battery efficiently and promptly even if the output of the solar battery fluctuates.

In the charging system of the present invention, the internal battery 4 is a lithium ion battery, the discharge stop voltage stored in the memory circuit 7 is set to 3.0 V to 3.5 V / cell, and the discharge restart voltage is higher than the discharge stop voltage. And 3.5 V / cell to 3.9 V / cell.
The above charging system can quickly and efficiently charge the externally connected battery with the output of a natural energy generator such as a solar battery while optimally controlling the power stored in the lithium ion battery of the built-in battery.

The charging system of the present invention can charge the external connection battery 3 by connecting the portable apparatus 30 to the charger 1 as a battery in which the external connection battery 3 is built in the portable apparatus 30.
The above charging system can efficiently and quickly charge the external connection battery built in the portable device.

The charging system according to the present invention includes a charging start switch 12 that can be operated manually by the control unit 5, and externally charges the external connection battery 3 by discharging the internal battery 4 with an input signal from the charging start switch 12. It is possible to start charging of the external connection battery 3 by controlling the battery charging state.
The above charging system can efficiently charge the external connection battery by starting charging by pressing the charging start switch.

It is a graph which shows the state in which the charging system concerning one Example of this invention charges an external connection battery. 1 is a block diagram of a charging system according to an embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below exemplifies a charging system for embodying the technical idea of the present invention, and the present invention does not specify the charging system as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The charging system shown in FIG. 2 includes a natural energy power generation device 2 that converts natural energy into electricity, and a charger 1 that is connected to the natural energy power generation device 2. The charger 1 includes an internal battery 4 connected to the natural energy power generation device 2 and charged with electric power input from the natural energy power generation device 2, and an external connection battery 3 connected to the outside with the internal battery 4. And a control unit 5 that controls charging and controls charging of the internal battery 4 by the generated power input from the natural energy power generation device 2. The above charging system charges the built-in battery 4 of the charger 1 with the generated power input from the natural energy power generation device 2, discharges the built-in battery 4 charged by the natural energy power generation device 2, and externally connected battery 3. To charge.

  In the charging system shown in the figure, the natural energy power generation device 2 is a solar cell 20. The solar battery 20 has a rated output that is large enough to charge the built-in battery 4 in one to five days. The solar cell 20 can fully charge the built-in battery 4 quickly by increasing the rated output. However, a solar cell with a large rated output is expensive. In addition, since a solar cell having a large rated output has a large outer shape, it is inconvenient to carry in a portable charging system. For this reason, the rated output of the solar cell is set such that the rated output is, for example, 1 W to 10 W in consideration of cost and portability.

  However, the present invention does not specify the natural energy power generation device as a solar cell, and does not specify the output of the solar cell within the aforementioned range. The natural energy power generation device can be any power generation device whose output varies depending on the natural environment, such as all devices that convert natural energy into electric energy, for example, wind power generation devices.

  The built-in battery 4 is a battery charged by the solar battery 20, and its rated capacity is made larger than the rated capacity of the external connection battery 3. For example, the rated capacity of the internal battery 4 is 1.5 to 3 times the rated capacity of the external connection battery 3. The built-in battery 4 can fully charge the connected external connection battery 3 even when the solar battery 20 is in a fully charged state and does not generate power. However, the built-in battery can have a rated capacity smaller than that of the external connection battery. For internal batteries with a small rated capacity, connect the external connection battery in a fully charged state, and the external connection battery cannot be fully charged with only the internal battery, but the external connection battery is fully charged with both the solar battery and the internal battery. be able to.

  The built-in battery 4 is a lithium ion battery. Lithium-ion batteries are small and can have a large rated capacity, so they can be used conveniently in portable charging systems. In addition, the lithium ion battery can be efficiently charged from the solar battery 20. This is because the charging efficiency for a small current can be increased. However, the built-in battery is not specified as a lithium ion battery. As the internal battery, any rechargeable battery such as a nickel metal hydride battery or a nickel cadmium battery can be used.

  The control unit 5 charges the internal battery 4 with the external battery charging state in which power is supplied from the internal battery 4 to the external connection battery 3, and the external battery charging state is stopped and the electric power input from the natural energy generator 2 is used. Switching unit 6 that switches between the internal battery charging state, the discharge stop voltage of the internal battery 4 that switches the external battery charging state to the internal battery charging state, and the full charging voltage of the internal battery 4 that switches from the internal battery charging state to the external battery charging state A storage circuit 7 for storing a discharge resumption voltage set to a lower voltage, and a voltage detection circuit 8 for detecting the voltage of the built-in battery 4.

  The switching unit 6 includes a switching circuit 10 and a switching element 11 that is controlled to be turned on / off by the switching circuit 10. The switching circuit 10 controls the switching element 11 by comparing the voltage of the built-in battery 4 detected by the voltage detection circuit 8 with the discharge stop voltage and the discharge restart voltage stored in the storage circuit 7. When the built-in battery 4 is discharged, the switching circuit 10 compares the voltage of the built-in battery 4 detected by the voltage detection circuit 8 with the discharge stop voltage. When the voltage of the built-in battery 4 decreases to the discharge stop voltage, the switching circuit 10 11 is switched off, and the discharge of the internal battery 4 is stopped. The switching circuit 10 detects the voltage of the built-in battery 4 being charged by the voltage detection circuit 8 and compares this detection voltage with the discharge resumption voltage. When the voltage of the built-in battery 4 rises to the discharge restart voltage, the switching element 11 is switched on and the discharge of the built-in battery 4 is restarted. In this state, the internal battery 4 charges the external connection battery 3. The switching unit 6 can discriminate between the external battery charge state and the internal battery charge state of the internal battery 4 from the change in the voltage of the internal battery 4.

  2 is provided with a charge start switch 12 that is manually operated by the user. The charging start switch 12 is connected to the switching circuit 10 by a push button or the like that can be operated from a case (not shown) of the charger 1. The switching unit 6 switches on the switching element 11 by a charge start signal input from the charge start switch 12 and controls the external battery charging state in which the external battery 3 is charged by the built-in battery 4. That is, the switching unit 6 starts charging the external connection battery 3 with the built-in battery 4 in response to a charge start signal from the charge start switch 12. The control unit 5 detects the voltage of the built-in battery 4 with the voltage detection circuit 8 after detecting the charging start signal and switching the switching element 11 on, or before switching the switching element 11 on. When the detected voltage of the built-in battery 4 is lower than the discharge stop voltage, the on-switching element 11 is switched off, and the built-in battery 4 is charged by the solar battery 20 without switching the switching element 11 on. To do. The charging system including the charge start switch 12 controls the switching element 11 to be turned on or off by a charge start signal input from the charge start switch 12 to set the external battery charge state or the internal battery charge state. When the voltage of the built-in battery 4 is higher than the discharge stop voltage, the control unit 5 switches on the switching element 11 with the charge start signal to set the external battery charging state. After that, when the voltage of the built-in battery 4 decreases to the discharge stop voltage, the switching element 11 is switched off and the internal battery is charged. Since the above charging system can start charging of the external connection battery 3 by pressing the charging start switch 12, the timing at which the user starts charging the external connection battery 3 can be specified.

  However, in the charging system of the present invention, it is not always necessary to provide a charging start switch in the control unit. The switching unit 6 detects whether or not the external connection battery 3 is connected, detects the voltage of the internal battery 4 in a state where the external connection battery 3 is connected, and the external battery charging state and internal battery charging state of the internal battery 4 This is because it can be controlled. The connection state of the external connection battery 3 can be determined by controlling the switching element 11 to be on and detecting the current flowing through the switching element 11. For example, when the switching element 11 is switched on and current flows through the switching element 11, it is determined that the external connection battery 3 is connected, and when no current flows, the external connection battery 3 is determined not to be connected. This charging system compares the voltage of the built-in battery 4 with the discharge stop voltage when the external connection battery 3 is connected, and switches the switching element 11 of the switching unit 6 on when the voltage is higher than the discharge stop voltage. The external connection battery 3 is charged by the built-in battery 4 as the external battery charging state. In the state where the external connection battery 3 is connected and the voltage of the internal battery 4 is lower than the discharge stop voltage, the switching element 11 is turned off to stop the charging of the external connection battery 3 and enter the internal battery charging state.

  The memory circuit 7 stores a discharge stop voltage and a discharge restart voltage. The discharge stop voltage is set to a voltage at which the built-in battery 4 is not overdischarged, that is, a voltage equal to or higher than a voltage at which the remaining capacity of the built-in battery 4 is zero. For example, in a charging system in which the built-in battery 4 is a lithium ion battery, the discharge stop voltage is set to 3.3 V as shown in FIG. However, the discharge stop voltage can be set to, for example, 3.0 V to 3.5 V / cell in a lithium ion battery. If the discharge stop voltage is too low, the tendency to overdischarge the built-in battery 4 becomes strong. Conversely, if the discharge stop voltage is too high, the external connection battery 3 is charged when the external connection battery 3 is connected with the built-in battery 4 being discharged. Has a drawback that it takes time to charge the built-in battery 4 until the operation starts. Therefore, the discharge stop voltage is set to an optimum voltage at which the external connection battery 3 can be quickly charged by the solar battery 20 without overdischarging the internal battery 4.

  Further, the discharge resumption voltage is lower than the full charge voltage of the built-in battery 4, and is set to 3.7 V as shown in FIG. 1 in the charging system using the built-in battery 4 as a lithium ion battery. However, this discharge resumption voltage is higher than the discharge stop voltage in a charging system in which the built-in battery 4 is a lithium ion battery, and can be set to, for example, 3.5 V / cell to 3.9 V / cell. . If the discharge stop voltage is too low, the capacity that can be charged to the internal battery 4 by the solar battery 20 becomes small, and the external connection battery 3 cannot be efficiently charged by the internal battery 4. On the contrary, if the discharge stop voltage is too high, It takes a long time to charge the battery 4, and the time for switching from the built-in battery 4 to the charging of the external connection battery 3 becomes long, and the external connection battery 3 cannot be charged quickly. Therefore, the discharge stop voltage is set to an optimum voltage that allows the external connection battery 3 to be quickly charged by the solar battery 20 while the external connection battery 3 is efficiently charged by the internal battery 4.

  The voltage detection circuit 8 detects the voltage of the built-in battery 4 and outputs the detection voltage to the switching circuit 10. The voltage detection circuit 8 detects the voltage of the built-in battery 4, converts an analog signal of the detected voltage into a digital signal, and outputs it to the switching circuit 10.

  When the charge start signal is input from the charge start switch 12, the switching circuit 10 compares the voltage signal of the built-in battery 4 input from the voltage detection circuit 8 with the discharge stop voltage stored in the storage circuit 7. When the voltage of the built-in battery 4 is higher than the discharge stop voltage, the switching element 11 is switched on to start the discharge of the built-in battery 4. That is, the internal battery 4 is discharged and charging of the external connection battery 3 is started. In this state, when the voltage of the built-in battery 4 is lower than the discharge stop voltage, the switching circuit 10 controls the switching element 11 to be turned off. In this state, the internal battery 4 is charged by the solar battery 20 and the external connection battery 3 is not charged. When the switching circuit 10 detects the connection of the external connection battery 3, the charging system without the charge start switch 12 compares the voltage of the internal battery 4 with the discharge stop voltage, and the voltage of the internal battery 4 is higher than the discharge stop voltage. The switching element 11 is controlled to be turned on, and when it is lower than the discharge stop voltage, the switching element 11 is controlled to be turned off.

The switching circuit 10 repeats the following operation to charge the external connection battery 3.
(1) External battery charge state The switching circuit 10 detects the charge start signal input from the charge start switch 12 or detects the connection of the external connection battery 3, and switches the switching element 11 on to turn on the internal battery. 4, the external connection battery 3 is charged. In the external battery charging state, the voltage detection circuit 8 detects the voltage of the internal battery 4 and outputs a voltage signal to the switching circuit 10. The switching circuit 10 compares the voltage signal input from the voltage detection circuit 8 with the discharge stop voltage stored in the storage circuit 7. The voltage of the internal battery 4 that is discharged by charging the external connection battery 3 gradually decreases. In the charging system in which the rated output of the solar cell 20 is smaller than the charging current of the external connection battery 3, even when the solar cell 20 is in the rated output state, as shown in FIG. The voltage of 4 gradually decreases. Even in a charging system in which the rated output of the solar battery 20 is larger than the charging current of the external connection battery 3, the output of the solar battery 20 decreases due to clouding or rain and becomes smaller than the charging current of the external connection battery 3. There is. When the voltage of the internal battery 4 decreases and the voltage signal input from the voltage detection circuit 8 decreases to the discharge stop voltage, the switching circuit 10 switches off the switching element 11 and stops charging the external connection battery 3. Thus, the internal battery 4 is charged with the solar battery 20 being charged.

(2) Internal battery charge state In this state, the internal battery 4 is charged by the solar battery 20 without discharging the internal battery 4. The voltage of the built-in battery 4 to be charged gradually increases. Even in this state, the voltage of the internal battery 4 is detected by the voltage detection circuit 8. The switching circuit 10 compares the voltage of the internal battery 4 detected by the voltage detection circuit 8 with the discharge resumption voltage, and when the voltage rises to the discharge resumption voltage, the switching circuit 11 is turned on, and the external battery 3 is connected with the internal battery 4. The external battery is charged in (1).

  As described above, the switching circuit 10 switches the switching element 11 on and off, alternately switches between the external battery charging state and the internal battery charging state, and charges the external connection battery 3 with the output of the solar battery 20.

  As described above, in the state where the output of the solar cell 20 is smaller than the charging current of the external connection battery 3, the internal battery charge state and the external battery charge state are alternately switched to charge the external connection battery 3. However, when the output of the solar battery 20 is larger than the charging current of the external connection battery 3, the voltage of the internal battery 4 does not decrease when the external connection battery 3 is charged by the internal battery 4. Therefore, in this state, if charging of the external connection battery 3 is started in a state where the voltage of the internal battery 4 is higher than the discharge stop voltage, the voltage of the internal battery 4 does not drop to the discharge stop voltage. . For this reason, the switching element 11 is kept on, and the external connection battery 3 is charged by the solar battery 20. However, if the voltage of the built-in battery 4 is lower than the discharge stop voltage when charging is started, the switching element 11 is kept off to enter the internal battery charge state, and the voltage of the built-in battery 4 stops discharging. After rising to the voltage or the discharge restart voltage, the switching element 11 is switched on, and charging of the external connection battery 3 is started as an external battery charging state.

  The external connection battery 3 is fully charged and charging is stopped. A charge stop circuit (not shown) for detecting the full charge of the external connection battery 3 and stopping the charge is provided in the switching circuit 10 of the charging system. In the charging system in which the portable device 30 incorporating the external connection battery 3 is connected to the charging system and the external connection battery 3 is charged, a charging stop circuit (not shown) is incorporated in the portable device 30. When detecting that the external connection battery 3 is fully charged, the charging stop circuit built in the switching circuit 10 switches the switching element 11 off and stops charging. When the external connection battery 3 is fully charged, the charge stop circuit built in the portable device 30 switches off a built-in switching element (not shown) to stop the charge of the external connection battery 3.

  The charging system of FIG. 2 includes a charging circuit 13 that charges the built-in battery 4 with the output of the solar battery 20. The charging circuit 13 is connected between the solar battery 20 and the built-in battery 4, and charges the built-in battery 4 with a preferable voltage and current by the output of the solar battery 20. The charging circuit 13 of the charging system using the built-in battery 4 as a lithium ion battery incorporates a constant voltage / constant current circuit, and charges the lithium ion battery of the built-in battery 4 with this constant voltage / constant current circuit. Furthermore, the charging circuit 13 also includes a circuit that detects the full charge of the built-in battery 4 and stops charging. The circuit for detecting the full charge of the lithium ion battery determines that the battery is fully charged when the charging current charged by the constant voltage / constant current circuit is smaller than a predetermined current. A charging system in which the built-in battery is a nickel metal hydride battery or a nickel cadmium battery can charge the built-in battery directly with the output of the solar battery without providing a constant voltage / constant current circuit. Therefore, this charging circuit includes a circuit for detecting the full charge of the internal battery and a circuit for detecting the full charge and stopping the charging of the internal battery.

  The above charging system preferentially charges the external connection battery 3 with the output of the solar battery 20. The external connection battery 3 is fully charged by alternately repeating the external battery charge state and the internal battery charge state. After the external connection battery 3 is fully charged, charging of the external connection battery 3 is stopped and the internal battery 4 is charged by the solar battery 20. When the internal battery 4 is fully charged, the charging of the internal battery 4 is also stopped.

  However, the charging system can fully charge the internal battery 4 with the solar battery 20 without connecting the external connection battery 3 and can fully charge the external connection battery 3 with the fully charged internal battery 4. That is, the external connection battery 3 is fully charged only in the external battery charging state. Further, even when the built-in battery 4 is charged with a larger capacity than the capacity capable of fully charging the external connection battery 3 with the solar battery 20, the external connection battery 3 can be fully charged with the internal battery 4. Even in this state, the external connection battery 3 is fully charged only in the external battery charging state.

DESCRIPTION OF SYMBOLS 1 ... Charger 2 ... Natural energy power generation device 3 ... External connection battery 4 ... Built-in battery 5 ... Control part 6 ... Switching part 7 ... Memory | storage circuit 8 ... Voltage detection circuit 10 ... Switching circuit 11 ... Switching element 12 ... Charging start switch 13 ... Charging circuit 20 ... Solar battery 30 ... Portable equipment

Claims (5)

A natural energy generator (2) that converts natural energy into electricity, and a built-in battery (4) that is connected to the natural energy generator (2) and is charged with the power input from the natural energy generator (2) And a charger (1) including a control unit (5) for controlling charging of an externally connected battery (3) connected to the outside with the internal battery (4),
The built-in battery (4) of the charger (1) is charged with the generated electric power input from the natural energy power generation device (2), and the built-in battery (4) is discharged to replace the external connection battery (3). A charging system configured to charge,
The control unit (5) stops the external battery charging state and the external battery charging state in which power is supplied from the internal battery (4) to the external connection battery (3) to charge the external connection battery (3). Switching unit (6) for switching the internal battery charging state for charging the internal battery (4) with the electric power input from the natural energy generator (2), and the internal battery for switching the external battery charging state to the internal battery charging state ( A storage circuit (7) for storing the discharge stop voltage of 4) and a discharge resumption voltage set to a voltage lower than the full charge voltage of the internal battery (4) for switching from the internal battery charge state to the external battery charge state; A voltage detection circuit (8) for detecting the voltage of the built-in battery (4),
In the external battery charging state in which the internal battery (4) supplies power to the external connection battery (3), the voltage of the internal battery (4) is detected by the voltage detection circuit (8), and the detected voltage is stored. When the discharge voltage drops to the discharge stop voltage stored in the circuit (7), the switching unit (6) switches the external battery charging state of the internal battery (4) to the internal battery charging state, and the internal battery charging state is switched to the natural energy. In a state where the internal battery (4) is charged by the power generation device (2), the voltage of the internal battery (4) is detected by the voltage detection circuit (8), and the detected voltage is stored in the storage circuit (7). When the discharge restart voltage is set lower than the stored full charge voltage of the internal battery (4), the switching unit (6) switches the internal battery charge state of the internal battery (4) to the external battery charge state. Repeat the external battery charge state and internal battery charge state to charge the external connection battery (3). Charging system formed by the.   The charging system according to claim 1, wherein the natural energy power generation device (2) is a solar cell (20).   The internal battery (4) is a lithium ion battery, the discharge stop voltage stored in the memory circuit (7) is set to 3.0 V to 3.5 V / cell, the discharge restart voltage is higher than the discharge stop voltage, The charging system according to claim 1 or 2, wherein the charging system is set to 3.5 V / cell to 3.9 V / cell.   The external connection battery (3) is a battery built in the portable device (30), and the portable device (30) is connected to the charger (1) so that the external connection battery (3) is charged. The charging system according to any one of claims 1 to 3.   The control unit (5) includes a charge start switch (12) that can be operated manually, and an input signal from the charge start switch (12) discharges the built-in battery (4) to provide an external connection battery (3). The charging system according to any one of claims 1 to 4, wherein charging of the external connection battery (3) is started by being controlled to an external battery charging state for charging the external battery.

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